Adjust formatting in unit system tests

[epenet]

Proposed change

Adjust black formatting in unit system tests
I think this is way more readable, but it goes against black standard rules so maybe it is not wanted?

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
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Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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  Updated by running python3 -m script.gen_requirements_all.
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[MartinHjelmare]

Alternatively add a comma after the last item in all tuples to have them all be multiline-formatted.

[frenck]

agreed

[epenet]

I don't think having all multiline really helps with clarity.
Maybe it is better to split the METRIC and US_CUSTOMARY tests?

[emontnemery]

The splitting improves readability IMHO